Engraving machine



March 14,1944.

A. B, SIMMONS 2,344,481 ENGRAVING MACHINE Filed Apri1.11,'1942 6Sheets-Sheet 1 March 14, 1944.,

A. a. SIMMONS 2,344,481

ENGRAVING MACHINE Filed April 11, 1942 6 Sheets-Sheet 2 I Ari/7W5. g/ /gyggns b IIITTORNE YS ENGRAVING MACHINE Filed April 11, 1942 6Sheets-Sheet 5 m5 INVENTOR TORNEYS are 14, 1944.. 'SIMMQNS 2,344,431

ENGRAVING MACHINE Filed April 11, 1942 6 Sheets-Sheet 4 mama/7s.YIQIVENTOR W W BY ATTORNEYS March 14, 1944. A. B. SIMMON 2,344,481

ENGRAVI'NG MACHINE Filed April 11, 1942 6 Sheets-Sheet 5 Arthur 8.Simmons I N V EN TOR A'T'roRlvEYs March 14, 1944. A. B. SIMMONS 2,

ENGRAVING MACHINE Filed April 11, 1942 s Sheets-Sheet 6 Arthur 5.5/mm0nsINVENTOR W/ BY mafia ATTORNEYS Patented Mar. 14, 1944 UNITED STATES.PATENT orrlcs ENGRAVING MACHINE Arthur B. Simmons, Rochester, N. Y.,assignor to Eastman Kodak Company, Rochester, N. Y., a corporationofNwJersey Application April 11, 1942, Serial No. 438,640

22 Claims.

This invention relates to engraving machines and more particularly tothe construction of engraving machines with which extremely accurateengravings may be made. It further relates to a machine particularlydesigned to re move small areas of a thin wax coating from a glass platewhich is to be engraved so that'the wax coating may protect the platefrom an etching fluid permitting the fluid to reach the part beingetched only through the lines, symbols or the like, which have been cutthrough the wax coating.

It has been extremely difficult in the past to provide a machine whichis sufiiciently free from vibration and from unnecessary play in thebearings to produce fine lines which may be extremely close together andwhich may contain letters, patterns, figures; or symbols which areextremely small in size, because the slightest vibration in any of theparts is suffi cient to spoil work. It has been customary to usepantographs' so that an operator would move a stylus over a master plateof considerable size, the pantograph reducing the movement of anengraving tool to a desired extent. However, it has been extremelydifiicult to reduce the vibration and bearing movement in suchpantographs sufficiently to permit the desired degree of accuracy inwork. This is particularly true where a comparatively large number ofwork pieces are to be engraved at one time.

One of the objects of my invention is to provide a pantograph operatedengraving machine in which a large number of pieces of work may beaccurately engraved at one time. Another object of my invention is toprovide a machine of the class described in which friction between allthe moving parts and a supporting frame is largely eliminated or atleast reduced to a minimum. Another object of my inxention is to providea machine in which extremely accurate bearings are provided between therelatively movable links of a pantograph so as to greatly minimize playbetween the relatively pivoted members. Another object of my inventionis to provide an engraving machine in which a large number. ofworkpieces may be simultaneously engraved and in which the effortrequired to move the engraving tools is reduced to a minimum. Stillanother object of my invention is to prevent vibrations of a building inwhich the engraving machine may be mounted from effecting the quality ofworkmanship of the engraving machine. Other objects will appear from thefollowing specification, the novel features work table adjustingmechanism;

being particularly pointed out in the claims at the end thereof. v

Coming now to the drawings wherein like reference characters denote likeparts throughout:

Fig. l is a. perspective view of an engraving machine constructed inaccordance with and embodying a preferred form of my invention, certainparts being omitted for'the sakeof clearness; 1

Fig. 2 is a perspective view of a portion of the work holding andlengraving to'ol supporting mechanism used with the engraving machineshown in Fig, 1;

Fig. 3 is a top plan view of a typical workpiece which has beenengraved, this part being shown on a considerably magnified scale;

Fig. 4'is a section through a workpiece in condition to be placed on thesupporting mechanism and showing a portion of an engraved line there-Figs. 5, 6 and '7 are all diagrammaticviews showing the pantographlinkage in differentfpositions which it may assume engraving work. Themovements shown'in' Figs. 6 and Tare on a considerably exaggeratedscale, since the maximum movement of the linkage is comparatively slightwith respect to the length of the various links; r Fig. 8 is afragmentary detail partially insection showing a pivotal support forcertain links and a pivotal connection between other links;

Fig. 9 is a fragmentary detail showing the stylus carrier;

Fig. 10 is a fragmentary top plan view showing a portion of theengraving tool carrying and supporting structure;

Fig. 11 is a fragmentary detail showing the Fig. 12 is a fragmentarysectional view through a pivot supporting a portion ofv the pantographlinkage;

Fig. 13 is a fragmentary detail section showin a portion of thevibration controlling support;

Fig. 14 is a fragmentary detail partially in section showing apantograph linkage float;

Fig. 15 is a perspective detail showing a pivotal connection between apair of pantograph links;-

Fig. 16 is a fragmentary perspective partially in section showing aflexible connection between a portion of two sections of apantographconnecting link;

Fig. 17 is a fragmentary plan view showing. a portion of the engravingtool carrierand associated parts; .J

Fig. 18 is a fragmentary sectional view showing a pivot between twopantograph links;

Fig. 19 is a detail sectional view through a master engraving plate,stylus and stylus slide.

Fig. 20 is a top plan view of a second embodiment of my invention,certain parts being omitted for the sake of clearness;

Fig. 21 is an enlarged fragmentary detail showing the engraving toolcarrying member; and

Fig. 22 is an enlarged side elevation showing the relation of theengraving tool and the workholding structure.

My invention includes a pantograph structure in which bearing play isreduced or eliminated by providing special bearings all lying in asingle plane. By preventing the pantograph links from turning and byforming the bearings of hardened steel balls, bearing difiiculties havebeen largely overcome.

In order to give some idea as to the nature of the work which can beaccomplished on my machine, I might point out that a typical piece ofWork may consist of a glass disc e of an, inch in diameter and of aninch in thickness and this disc may have a pattern engraved thereon suchas that shown in Fig. 3 or of anyother desired pattern.

Referring to Fig. 3, the. engraved lines. marked A and B may be from.0005" to .0007" in width and the reference character C. may be. .0025in height. It is, to. be. distinctly understood that these. figures are,merely examples of a typical workpiece and are by no means to beconsidered a. limitation. It is much easier to engrave l r sizeworkpieces with wider lines and it is considerably more. dimcult to.reduce the size of the work over that suggested in the typicalexample.

Broadly speaking, my engraving machine consists of a stylus I, which maybe supported by a plurality of links forming a pantograph referred tobroadly as 2, this pantograph causing a series of engravingtools 3 tomove relatively to a series of work pieces 4 to reproduce on eachworkpiece a pattern 5 from a master plate I35 which is. of many timesthe size of the finely engraved workpieces. For instance, I find that itis often convenient to move the stylus a distance 20 to 25 times asgreat as the distance that the workpieces moved in the engravingoperation.

When the engraving is as fine as mentioned above, it is necessary toreduce all play between parts to a minimum; it is necessary to reducefriction between the moving parts to a minimum; and it is extremelynecessary toreduce vibration to a minimum. In order to accomplish theseends I have provided a machine, a typical example of which will now bedescribed. Referring to Fig. 13, I provide a support which will absorbbuilding" vibrations, this support preferably consisting of a number ofblocks III, which may support rubber pads H on which I-beams |2 mayrest, these I-beams supporting blocks [3 and I4 separated by a rubberpad |5 which may have a series of grooves Hi to make the pad moreresilient. On top of the blocks 4 there are transverse channel membersl'lacross which transverse channel members l8 may pass, these channelmembers being welded together to form a rigid support. Above the channelmembers l8. are welded plates I9 which may form. the bottom of the tanks20, the edges of these tanks being formed by the plates 2|. Since Fig.13 shows one corner of one of the main tanks 20 of which there are two,it can readily be seen that the structure. supporting these tanks is anextremely rigid one and that the corner supports are built to absorb asmuch vibration as possible. The two main tanks 20, as shown in Fig. 1,are partially filled with a fluid medium such as oil 22, although ofcourse water could be used, but water is more susceptible to evaporationand to transmitting vibrations than is a comparatively light oil. Thesetanks support a plurality of pantograph floats designated broadly as 23.

Each of the floats, as best shown in Fig. 14, may consist of a circularor other shape element 24 having relatively high sides 25 and supportingat 26 an upwardly extending rod 21 threaded at 28 and carrying two nuts29 and 3|], one on each side of a pantograph link broadly designated at2. Some of the pantograph links carry quite a number of these floats,whereas other links may have only one float, the floats being arrangedto properly support all of the links.

The pantograph as indicated especially in Figs. 5 to- '7 may consist ofa plurality of links pivotal'ly supported and so arranged that by movingthe stylus I, the engravingtools 3 may be moved through the same patternand to much less extent. In: the present instance the pantograph maycomprise a series of transverse links 30, 3|, 32 and 33, links 3| and 32being pivotally mounted at 34 and 35 to the frame of the machine so asto be hingedly attached thereto. The stylus I is preferably carried by aconnecting link which may be composed of the sections 36- and 3'! whichare hingedly attached at 38 and 3.9 to the link members 40- and 4|. Aswill be more fully described later, the hinge elements 38. and 39 permitthe stylus. to be moved verticallywithout affecting the movement; of thelinkage 3|, 32, 36 and 31 because this, movement, of the stylus may becomparatively slight say inch. The transverse links 30, 3|, 32' and 33-are connected by connecting links 42 and 43 and between all of thetransverse links there are pivotal connections of a special constructionbest shown in Figs. 15 and 18. For instance, Fig. 15 shows a typicalhinge connection between links 43 and 33. Each of these links is formedof thin, light-weight tubular material such as thin aluminum tubes. Eachof the tubes is provided with a sleeve 45 through which a setscrew 46passes, this setscrew being adapted to hold the sleeve 45 in the desiredposition. The sleeves are preferably equipped with holes 41 tofacilitate assemblingthe sleeves in the proper position and each sleeve,as indicated in Fig. 18,'is provided with a care.- fully formed v-shaped(in cross section) countersunk portion 48. These twocountersunk portionsare vertically arranged and a steel ball 49 is held inplace merely bythe weight of the link 43 resting on the. link 33. Thus, each pivotalconnection consists of a single steel ball so that: this eliminatesanyplay between the two pivoted links. While I have described, only onepivotal connection as illustrated in Fig. 15, it is to be understoodthat. the same type of connection is provided at each of the cornersshown in Fig. 5 and numbered 5.|, 52, 53, 54, 55, 5G, 51' and 58.

It should be noticedthat the connecting link holding the stylus is madeup of a series of sections and that hinges 38 and 39 are providedbetween these sections. These hinges are identical and, as shown in Fig.16, they consist of blocks and 6| attached to the links such as 36 and49, these blocks being grooved at 62 and 63 to support the hinged memberwhich consists of a thin, metal plate 64. This plate is capable ofmoving to permit the stylus I to be raised or lowered a short distance,but it cannot turn transversely of the plate 64. This is particularlytrue because it will be noticed from Fig. 1 that each of the sections35, 40, and 4|, 31 are provided with a bracing which consists oftransverse rods 65 passing through the links 36 and 31 and a pair ofwire braces 66 and 61 connected both to the rods 36 and 31 and to therods 40 and M. Thus, this bracing also prevents sidewise lateraldisplacement of the connecting member links which is very essential whenfine work is to be done. The braces also prevent even the very slightspringing of the tubular links which conceivably might occur without thebraces.

It should be noticed that the arrangement of floats is such that thelinks 36 and 31 cannot readily turn because of the transverse rods IIIwhich support spaced floats II and I2 so that the links 36 and 31 areheld in a horizontal position.

The floats supporting the links 30 and 33 are alike in that each oftheselinks utilizes four floats 13, 14, I and 1.6, floats I4, and I5also being supported by a transverse rod 11 so that these links will befloated in a horizontal position. Links 3| and 32 are each provided witha similar arrangement at one end, there being three floats 18, I9 and80, floats I8 and 80 being supported by a transverse rod 8 I The shortconnecting links 42 and 43 are primarily supported by the transverselinks but I have found it desirable to provide a single float 82 carriedby a rod 83, since this prevents the links 43 and 42 from tending torotate.

The hinge connections of the transverse links 3| and 32 with the machineframe at 34 and 35 are important and are shown in detail in Fig. 8. Inthis figure it will be noticed that the link 32 carries a collar 84 withV-shaped counter sunk portions 85 spaced vertically with respect to eachother to support steel balls 86 and 81 which rest in the V-shapedcounter-sunk portions 88 and 89 in the bearing rods 90 and 9I. Rod 90 isfixedly attached by the bolt 92 to the frame 93 and rod 9I is slidablyattached in the cup member 94 which contains a spring 95 to thrustupwardly on the bearing rod 9|. Thus, the upward force of this springkeeps the two balls 86 and-81 in position and a very delicate hinge isthus formed. The second frame support 96 which carries the hingeconnection 34 is exactly like the showing of Fig. 8. As indicated inFig. 12, the lower bearing block 91, which is secured to the end memberI04 adjacent the pivot 35, is

provided with a V-shaped groove 98 for the lower bearing ball 99 so thatthe sleeve I00, which positions the ball 99, may have extremely slightlateral movement as the ball 99 moves in the groove 98 which is of anextent sufficient to take care of the difference in position between theends of the links 42 and 43 which occurs in moving the pantograph andthe engraving tool. The bearing block 91', which is secured to the endmember I04 adjacent the pivot 34, is provided with a counter-sunkportion similar to 98, as shown in Fig. 12, for receiving a ball uponwhich the sleeve I09 rests.

The engraving tools 3, as best shown in Fig, 2,

5-7 and 17. The frame I03 includes end members I04'and connecting rodsI05 and I 06 which, as best shown in Fig. 10, are supported by threesets of floats in three tanks. The tanks I01. and I09 each carries threefloats I09 and the tank IIIl carries a single float I II all of thesefloats being connected to the frame or supporting members as indicatedin Fig. 14. It should be noticedthat the floats are of diiferent shapesand sizes, as also are the tank members, these being selected purely forthe sake of convenience and for supporting the required weight. While itwould no doubt be possible to make a machine with a single tank, I findit much more convenient to provide a plurality of tanks as indicated inthe present embodiment of my invention.

The engraving tool-holding frame preferably supports a large number ofengraving tools-in the present embodiment30 may beused. Since each pairof engraving tools is exactly alike,-I will describe only one pairspecifically, a typical pair being illustrated in Fig. 2.

' The engraving tools are supported by castings II 3 and H4 and each ofthese'castings is provided with light triangular supports H5 preferablymade of rigid tubing having welded crossbars I I 6. The right-handengraving tool carrier shown in Fig. 2 is supported by a leaf spring II!which is rigidly attached by means. of screws M8 to the top of the frameba'r I03. Thus the spring I I! may flex when the wire I I9, which isattached to the casting I I3 at one end and to a supporting disk I20 atthe oppositeend, changes in length.

This change in length is made by passing an electric current through acircuit including the bar I2| and the bar I22 through the wire II9, theheat altering the length of the wire a sufficient distance to raise andlower the engraving tool 3 to and from'the workpiece I25. The specificmeans for raising and lowering the engraving tool 3 forms no part of thepresent invention and is not claimed herein. It is fully illustrated anddescribed in the copending application Serial No. 438,301, filed April1, 1942, in the name of Daniel B. McRae and entitled Engraving machine.This application resulted in Patent No. 2,327,811 granted August 24,1943.

The left-hand engraving 'tool referring to Fig. 2 differs from theright-hand tool in that the triangular frame is attached to a springplate I24 which is attached to the bottom of the frame bar I03.Otherwise, the structure is just the same as this tool may be raised andlowered against spring pressure by the wire H9 in exactly the samemanner as the first tool.

It will be noticed from Fig. 10 that the entire frame, of which bar I03is a part, is mounted to be moved when the stylus is moved andconsequently all of the engraving needles 3 are moved at the same timeand by the same mechanism.

The workpieces I25 are held stationary on a worktable I26 a portion ofwhich is shown in Fig. 2. This'table is provided with spring members I21along the'rear edge I28, these spring members tending to thrust theworkpieces I25 forwardly against a pairof setscrews I29 which passthrough the upstanding flange I30. These setscrews can, of course, bemoved to initially set the workpieces in their proper position withrespect to the engraving tools 3.

Before the workpiece I25 is mounted on the .work table I26 it is placedin a flanged ring I3I as indicated in Fig. 4, being backed up by a thicklayer of wax I32. On the upper surface of the workpiece there is a thinlayer of wax I33 and it is this wax coating which'is displaced by theengraving tool 3 to. make the mark as. indicated at B. After the, designhas been cut through the wax coating I33 the workpieces are subjected toa suitable etching fluid such as hydrofluoric acid gas.

The design which is to be engraved on the workpiece I25, as for instancethe design shown in Fig. 3, is formed in a master plate on a greatlymagnified sketch. Referring to Fig, 1, it will be noticed that themaster plate I35 is provided with slots which are carefully laid out inthe proper pattern. The stylus may be as shown in Fig. 9 where the rod Iforms the stylus member, this rod passing through a ball I36 which iscarried by a plug I3I riveted to the connecting link 40. Partlysurrounding the ball I36 is a semi-spherical shell I38 which is attachedto a plug I39 carried by the connecting link 4!. This semi-sphericalmember is provided with an aperture I46 which permits relative movementbetween the ball I36 and socket I38. Extending upwardly from the stylusis a spring support I 4| which, as shown in Fig. 1, may include a springsection I42 which is attached at I43 to the ceiling I44 or to any othersuitable support. The spring support I42 is just strong enough to almostcounterbalance the weight of the transverse links 40 and 4| which mustbe raised slightly when the point or end I45 of the stylus is raisedfrom the masterplate I35, which, as above explained, is grooved in theproper pattern at 5 or from a slider I41 which may be used and which isbetter shown in Fig. 19. As shown in this figure, the point I45 of thestylus I may engage an aperture I48 in the slider, this slider having aweb I49 to engage and slide in the groove 5 in the master plate It isnot always necessary to use a slider I41 between the stylus point andthe master plate but it has been found desirable to use a slider in anypattern where two lines cross each other, because there is always atendency for the stylus point to engage the groove and, where groovescross, to slightly follow into one of the cross grooves. However, if aslider I 47 is used with a web I49 of appreciable lengthinstead of aspherical point like the point I45 of the stylus I-the web will passover any cross cuts in the master plate making a smooth and even stroke.However, if desired, the slider may be omitted. In fact, a slider isvery often omitted particularly where a number of master plates are usedone after the other to produce portions of a single pattern engraved ona workpiece. For instance, if desired, one master plate might be usedfor thelines shown at A in Fig. 3 and a second master plate might beused for the lines shown at B. If this type of master plate is usedthere would be no tendency for the stylus to follow any but the singleline appearing in the plate and consequently no slider would berequired.

The workpieces mounted in the flanged rings I3I' are, as aboveexplained, .mounted on the work table I26. This work table I26 must ofcourse be very rigidly made and its construction is more fully shown inFig. 11. As shown in this figure, it will be noted that the work tableI26 lies across a relatively heavy frame member which includes heavy endframes I56 which are pivoted at I5I to supports I52 and which at theirforward ends are supported on springs I53 carried by a frame member I54.The springs tend to thrust the end frame members I56 upwardly but thisupward movement is prevented by a cable I55 passing around a pulley I56pivoted at I51 to the frame member. This pulley can be turned by a strapI 58 which is attached. at one end I56 to. the. end of a screw I66 whichmay be turned by a wheel I61 preferably provided with a handle I62. Byturningthis handle, the work table I26 may be moved to the properposition for any desired setup of the engraving tools.

The end frames I56 are preferably connected by heavy webbing I64 to maketh work table as rigid as possible because of course any vibration inthis part would permit one or more Workpieces to vibrate and thus causepoor workmanship. (Fig. 1.)

The operation of this machine is actually quite simple after the initialsetup has been made. Assuming that the Work table has been properlypositioned and that all the engraving tools are properly positioned, theflanged rings I3I are all set beneath the engraving tools 3 by placingthem between the springs I21 and the previously adjusted setscrews I29.This can be done comparatively rapidly, and the twenty-five or thirtyworkpieces can be readily positioned.

The operator then places the stylus I in a slot 5 in the master plateand lowers the engraving tools 3 into contact with the workpieces, thetension in the springs I24 and II! being sufficient to press engravingtools through the upper coating of the wax I33.. The operator then movesthe stylus through the groove forming the pattern and this movement on amuch reduced scale provides one or more grooves in the wax coating I33corresponding to the pattern on the master plate I35. If the pattern isan intricate one, a number of master plates may be used withoutdisturbing the workpieces at all. Each time the engraving tool is to bemoved from one slot to another to produce a different portion of thecharacter such as the numeral C shown in Fig. 3, the operator raises theengraving tools a short distance such as .025", this movement takingplace smoothly and slowly as the Wires I I9 are heated electrically. Thespecific way this is done is described in the copending applicationabove referred to.

In moving the stylus Iit should be noticed that each time the stylusneeds to be raised the hinged elements 38 and 39 of the connecting linkreadily fiex a suificient amount to permit the necessary stylusmovement. However, there is no side defiection of the connecting linkbecause of the bracing structure shown in Fig. 1 which includes thetransverse rods 66 and the guy wires 65. Thus, while the stylus may movevertically a short distance without disturbing the links, any othermovement of the stylus causes the links to move. Referring to Fig. 5, ifthe stylus I is moved upwardly with respect to Fig. 6, the links willassume the position shown in this figure. However, this figure shows astylus which has been moved both up and to the left with regard to Fig.5; whereas in Fig. '7 the stylus has been moved down and toward theright. The movement of the stylus in Figs. 5 to '7, inclusive, isgreatly exaggerated with respect to the length of the links as actuallythe stylus ordinarily moves less than fifteen inches; whereas the stylusconnecting links 4| and 37 may be, in the embodiment of my inventiondescribed, 5 or 6 feet long. In any event the entire carriage carryingthe engraving tools 3 is moved through the same pattern as the stylusexcept that it is on a greatly reduced scale. With the machine abovedescribed it is thus possible to produce thirty workpieces Which aresimultaneously engraved and which may be then treated with a desiredetching fluid.

While I have described a preferred embodiment of my engraving machinewhich is provided with the double set of transverse link construction, Ican also provide a simplified pantograph with a single set of links asshown in Fig. 20. The apparatus shown in this figure is somewhat lessaccurate than the apparatus which has been previously described, butnevertheless satisfactory work for many purposes can be done with thisembodiment of my invention. Referring to Fig. 20, a simplifiedpantograph may consist of approximately one-half of the parts shown inthe double type pantograph of Fig. 1. Thus, the engraving tool I may becarried by a support I1I in which it may be heldby a setscrew I12, asshown in Fig. 21, the support I1I in turn being carried by the plate I13which is provided with a cutout I14. Plate I13 is supported by the blockI15 which extends upwardly'from the end of plate I13 and encircles thepantograph arm I16. There is a slight spring action downwardly on thearm I13, the downward movement being limited by the transverse arm I11which is pivoted on the balls I18 and I19 supported by the rod I80 andthe block I8I, both being carried by the upwardly extending framecasting I82. This pivotal support may be exactly the same as thatpreviously described in connection with Fig. 8.

The work I83 may be carried by a spring arm I84 attached to the memberI85 supported by a portion of the frame I86. This spring arm is normallythrust downwardly away from the stops I81, as best shown in Fig. 22. Inorder to hold the work I83 in engraving position, a cable I88 isattached to the arm I84 and passes over a sheave I89 pivotally supportedat I90 on an upstanding rod I9I. The other end of the cable I88 isattached to a hand lever I93 pivoted on the bracket I92 adjacent a chairI95 (Fig. 20) on which the operator may sit so that his'left hand mayengage the hand lever I93 while his right hand may move the stylus I94over the master plate I35 which is grooved at I96 with the pattern to beengraved on a reduced scale on the work I83.

The pressure of the engraving tool I10 on the work I83 is determined bythe downward pressure of the spring arm I13, since an operator by movingthe hand lever I93 downwardly holds the spring arm I84 upwardly againstthe stops I81 during the engraving operation. Each time the stylus is tobe moved vertically, the operator permits the hand lever I93 to rotatein a counterclockwise direction with respect to Fig. 22. This permitsthe work I83 to be lowered away from the engraving tool I10. The handleI93 must be held in its lowermost position during all of the time inwhich the engraving needle is to cut through the wax coating on the workI83.

The pantograph consists of the transverse levers I11 and I96 which arepivotally attached to the pantograph lever I16 by pivotal connections atI91 and I98. These connections need not be described in detailbecause'they are the same as the pivotal connections shown in Figs.

15 and 18-that is the pantograph arms are provided with sleeves havingcounter-sunk areas in which pivots in the form of balls 49 are used.

The purpose of a cutout I14 in the spring arm I13 is to permit thesleeves I91 and I98 to pass through the spring arm without touching theparts of the pivotal connection.

The pantograph arms I11 and I96 have pivotal connections at I99 and 200with a single joined connecting link 20I. This connecting link has ahinge at 202 like the hinge described in connection with Fig. 16 whichwill permit vertical movement of the link section 203 relative to 20Iwhen a stylus I94 carried on the end of the link 203 is movedverticallly. The link sections MI and 203 are reenforced againstsidewise movement by means of a bracing rod 204 passing through link 203and supporting two guy wires 205 and 206, these wires being connectedtothe opposite ends of the links 20I and 203.

The transverse links I96 and I11 are both supported by floats, link I11by the float 201 and 208 carried by the transverse arm 209 supported onlink I11. Link I96 is supported by the floats 2I0, 2II, 2I2, and 2I3.Floats 2H and 2I2 are carried by a transverse rod 2I4. Link I16 has asingle float 2I5 carried by the transverse rod 2I6 and link 20I has asingle float 2I1 carried by the transverse rod 2I8. Since all of thesefloats are substantially like the float shown in Fig. 14 and may supportthe links of the pantograph in the same manner, it is unnecessary todescribe them further except to point out that in this instance all ofthe floats may be supported by a fluid such as oil or water 220 in asingle tank 22I.

The operation of the second embodiment of my invention is somewhat morediificult than that of the preferred embodiment because it requiressomewhat more skill on the part of the operator. The operator sits inthe seat I95 with his right hand on the stylus I94 and hisleft hand onthe hand lever I93. Assuming that work I83 has been mounted on the armI84, the operator moves the stylus to a starting position on the masterplate I35, which is normally at one end of one of the slots I96. He thenvery slowly and gently moves the hand lever I93 in the direction shownby the arrow in Fig. 22, thus causing the work I83 to move slowlyupwardly into contact with the engraving tool I10 and until the arm I84has come up against the stops I81. When this position is reached thedownward pressure on the engraving tool I10 is controlled by the springarm I13. The operator then moves the stylus I94 through its path andwhen the end of a slot is reached or when a different part of thepattern is to be engraved the hand lever I93 is moved slowly in areverse direction from that shown by the arrow in Fig. 22, thuspermittingthe arm I84 to move the work I83 away from the engraving toolor needle I10.

An important feature of both forms of my invention is that all of thecontact points are kept in the same horizontal plane. That is, thevarious pivotal points winch are formed by the hardened steel ballsbetween the phtoograph sections are all preferably in the samehorizontal plane and this is also true of the engraving tool and thestylus. Thus if this plane is accurately maintained and if the variouslinks of the pantograph are prevented from turning or twisting relativeto each other, a high degree of accuracy in the movement of the variousparts can be obtained,

engraving tool of an engraving machine and comprising a plurality ofhinged links connecting the stylus and engraving tool, each of saidhinges comprising a pair of spaced bearing members one carried by eachlink, each pair of bearing members including facing countersunk portionsand a single ball lying in both countersunk portions on which one linkmay turn relatively to another, and means spaced from the hinges forholding. the counter-sunk portions in vertical alignment. r

2. A pantograph for connecting the stylus and engraving tool of anengraving machine and comprising a plurality of hinged links connectingthe stylus and engraving tool, each of said hinges comprisinga pair ofspaced bearing members one carried by each link, each pair of bearingmembers including facing countersunk portions and a single ball lying inboth countersunk portions, means separate from the hinge for holding thecounter-sunk portions in vertical alignment, the weight of one linkholding the ball in the countersunk bearing portion of the link on whichit rests.

3. A pantograph for connecting the stylus and egnraving tool of anengraving machine and comprising a plurality Qfhinged links connectingthe stylus and engraving tool, certain links lying over other links,hinges between the links including bearing members, a countersunkportion in each bearing member and a single ball lying in the twocountersunk portions, means spaced from the hinges for holding thecountersunk portions in vertical alignment, the weight of the overlyinglinks forming the sole means for holding the ballformingthe hingebetween the th two countersunk areas of the bearing members in place.

al. An engraving machine including a pantograph, a stylus carriedthereby, an engraving tool operable by the pantograph, said pantographcomprising a linkage, a support, a pair of transverse links included inthe linkage and hinged to the machine, a link included in the linkageconnecting said transverse links and hinged thereto, said connectinglink including centrally thereof a stylus holder, and ilexible elementsinserted in the connecting link on each side of the stylus holder,whereby the connecting link may cause the flexible elements to fie whensaid stylus is moved vertically.

5. An engraving machine including a pantograph, a stylus carriedthereby, an engraving tool operable by the pantograph, said pantographcomprising a linkage, a support, a pair of transverse links in'cluded inthe linkage and hinged to the support, a link included in the linkageconnecting said transverse links and hinged thereto, isai'd connectinglink including centrally thereof a stylus holder, and flexible elementsinserted in the connecting link on each side of the stylus holder,comprising flat leaf springs adapted to flex vertically but nothorizontally to permit vertical movement of the stylus. e v N r v I 6.An engraving machine including a pantograph, a yl s c rri d ereb an enra n tool operable by the pantograph, said pantograph comprising alinkage, a support, a pair of transverse links inclnded in the linkageand hinged to the support, a link included in the linkage connectingsaid transverse links and hinged thereto, said connecting link includingcentrally thereof a stylus holder and flexible elementsinserted in'tlieconnecting link'o'n eac'h side bf the 15- stylus holder comprising flatleaf springs adapted to flex vertically but not horizontally to permitvertical movement of the stylus, and means attached to said connectinglink to prevent any but vertical flexing of the flexible members.

7. An engraving machine including a .pan'tograph, a stylus carriedthereby, an engraving tool operable by the pantograph, said pantographcomprising a linkage, a support, a pair'of transverse links included inthe linkage and hinged to the support, a link included in thelinkage'connecting said transverse links and hinged thereto, saidconnecting link including centrally thereof a stylus holder, andflexible elements inserted in the connecting link on each side of thestylus holder, comprising a flat leaf spring of a width greater thanthat of the connecting link, and extending horizontally to permit onlyvertical flexing of the springs and a hinge in the center of theconnecting member.

8. A pantograph for connecting the stylus and engraving tool of anengraving machine and comprising a linkage including transverse linkshingedly mounted to the frame of the machine, a connecting link hingedlyattached to the transverse links and having a hinge in the center, amoveable frame carrying the engraving tool, links included in thelinkage pivotally attached to the moveable frame, said links beinghingedly attached to the transverse links to be moved thereby when theconnecting link is moved by the stylus, said transverse links lyingsubstantially in one plane, said connecting link and said linkspivotally attached to the moveable frame at least partially overlyingthe transverse links, said hinge connections comprising facing coun=tersunk recesses carried by said links and balls lying in said recesses,each hinge turning on a single ball, and means separate from the hingesfor holding the counter-sunk recesses in vertical alignment.

9. A pantograph for connecting the stylus and engraving tool of anengraving machine and comprising a linkage including transverse linkshingedly mounted to the'frame of the machine, a connecting link hingedlyattached to the transverse links and having a hinge in the'center, amoveable frame carrying the engraving tool, links included in thelinkage pivotally attached to the moveable frame, said links beinghingedly attached to the transverse links to be moved thereby when theconnecting link is moved by the stylus, said transverse links lyingsubstantially in one plane, said connecting link and said linkspivotally attached to the moveable frame at least partially overlyingthe transverse'links, said hinge connections comprising facingcountersunk recesses carried by said links andballs lying in saidrecesses/each hinge turning'on a single ball, and means separate fromthe hinges for holding the counter-sunk recesses in vertical alignment,the balls being retained in position solely by the'weight of the linksoverlying the transverse links.

10. An engraving machine including, in combination, an engraving tool,a'stylusjanda move; ment multiplying linkage "therebe't'ween; saidlinkage including'transverse links in paralll pairs, a connecting linkhingedly attachedt'o the pairs of parallel links, one of 'each pairorpamnel links being pivotally mounted on'thefr'a'me c'fthe machineamount for said stylus on the coniiect-. ing link at the center thereofanda hingevin-tlije center of said link, means for'm'ihg'a partrof'said'connecting link'wliereby the partthrof carrying the stylus can be movedvertically without disturbing the linkage as a whole, an engraving toolcarrying frame, frame carrying links pivoted thereto and forming part ofthe linkage, hinge connections between the frame links and thetransverse links whereby the engraving tool carrying frame may be movedby said stylus through said linkage,- and means for supporting themultiplying linkage on floats moveable in an oil bath.

11. An engraving machine including, in combination, an engraving tool, astylus, and a move-, ment multiplying linkage therebetween, said linkageincluding transverse links in parallel pairs, a connecting link hingedlyattached to the pairs of parallel links, one of each pair of parallellinks being pivotally mounted on the frame of the machine, a mount forsaid stylus on the connecting link at the center thereof and a hinge inthe center of said link, means forming a part of said connecting linkwhereby the part thereof carrying the stylus can be moved verticallywithout disturbing the linkage as a whole, an engraving tool carryingframe, frame carrying links pivoted thereto and forming part of thelinkage, hinge connections between the frame links and the transverselinks whereby the engraying tool carrying frame may be moved by saidstylus through said linkage, and means for totally supporting thelinkage on floats with the exception of the pivotal mounts of thetransverse links.

12. An engraving machine, having, in combination, a pantograph, a stylusconnected to the pantograph, an engraving tool carried by thepantograph, said pantograph comprising a plurality of hinged links, andmeans for supportin said links comprising floats connected to saidlinks, and a tank of fluid supporting said floats.

13. An engraving machine, having, in combination, a pantograph, a stylusconnected to the pantograph, an engraving tool carried by thepantograph, said pantograph comprising a plurality of hinged links, andmeans for supporting said links, comprising floats, a post extendingupwardly from each float and connected to a link, and a tank of fluid tosupport the floats.

14. An engraving machine, having, in combination, a pantograph, a stylusconnected to the pantograph, an engraving tool carried by thepantograph, said pantograph comprising a plurality of hinged links, andmeans for supporting said links comprising floats, a post extendingupwardly from each float and connected to a link, and a tank of fluid tosupport the floats, a cross bar carried by at least some links, floatscarried at each end of the cross bar to prevent rotative movement ofsaid link relative to said linkage.

15. An engraving machine, having, in combination, a pantograph, a stylusconnected to the pantograph, an engraving tool carried by thepantograph, said pantograph comprising a plurality of hinged links, andmeans for supporting said links comprising floats connected to saidlinks, a moveable frame, engraving tools carried by said frame, aplurality of floats supporting said frame, hinge connections between theframe and pantograph linkage, and a fluid support for all of the floatsof the linkage and frame.

16. An engraving machine including, in combination, a pantographlinkage, a connecting link hingedly attached to certain other links ofthe linkage, said connecting link including two sections hingedtogether, a stylus carried at the 'hinge, each section comprising outerand inner sections,.the outer sections including float supports tendingto prevent rotative movement, a flexible spring plate of greater widththan the links connecting the two outer sections with the two innersections permitting flexing of the inner sections at their hingeconnection in a vertical direction, cross bars carried near the flexiblespring plates, and wires connecting the ends of each inner and outersections and the ends of the cross bars preventing flexure of the innerand outer sections in adirection other than vertie cal about said springplates. 1

17. An engraving machine including, in combination, a pantographlinkage, a connecting link hingedly attached to certain other links ofthe linkage, said connecting link including two sec tions hingedtogether, a stylus carried at the hinge, each section comprising outerand inner sections, the outer sections including float supports tendingto prevent rotative movement, a flexible spring plate of greater widththan the links connecting the two outer sections with the two innersections permitting flexing of the inner sections at their hingeconnection in a vertical direction, cross bars carried near the flexiblespring plates, and wires connecting the ends of each inner and outersections and the ends of the cross bar preventing flexure of the innerand outer sections in a direction other than vertical about said springplates and a counterbalance for the stylus adjacent the hingedconnection of the inner sections of said connecting link.

18. An engraving machine including, in combination, a pantographlinkage, a stylus connected thereto to move the linkage, an engravingtool, a frame carrying the engraving tool, floats connected to andsupporting the frame, frame moving links hingedly attached to the frameincluded in said linkage, transverse links hingedly attached to saidframe carrying links included in said linkage, two pivotal mountscarried by the engraving machine supporting two transverse links, andincluding countersunk bearings supporting a ball as a pivot, the hingeconnection between said frame and each of the frame moving linksconsisting of a countersunk bearing and a groove v-shaped in crosssection supporting a ball as a pivot, whereby said frame may be movedthrough the same pattern as the stylus through said pantograph linkagebut on a difierent scale.

19. An engraving machine including, in combination, a pantographlinkage, a stylus connected thereto to move the linkage, an engravingtool, a floating frame carrying the engraving tool, a reservoir of fluidon which said frame is floated, frame moving links hingedly attached tothe frame included in said linkage, transverse links hingedly attachedto said frame carrying links included in said linkage, two pivotalmounts carried by the engraving machine supporting two transverse links,and including countersunk bearings supporting a ball as a pivot, thehinge connection between said frame and each of the frame moving links,consisting of a, countersunk bearing and a groove V-shaped in crosssection supporting a ball as a pivot, whereby said frame may be movedthrough the same pattern as the stylus through said pantograph linkagebut on a different scale, floats supporting the entire pantographlinkage on said reservoir of fluid with the exception of the pivotalmounts for the transverse links whereby friction may be reduced to aminimum.

20. An engraving machine including, in combination, a pantographlinkage, a stylus connected thereto to move the linkage, an engravingtool, a floating frame carrying the engraving .tool, frame moving linkshingedly attached to the frame included in said linkage, transverselinks hingedly attached to said frame carrying links included in saidlinkage, two pivotal mounts carried by the engraving machine supportingtwo transverse links and including countersunk bearings supporting aball as a pivot, the hinge connection between said frame and each of theframe moving links consisting of a countersunk bearing and a grooveV-shaped in cross section-supporting a ball as a pivot, whereby saidframe may be moved through the same pattern as the stylus through saidpantograph linkage but on a different scale, floats supporting theentire pantograph linkage with the exception of the support thetransverse links derive from the pivotal supports, each float comprisinga flanged pan,'a rod attached centrally of the pan extending upwardly toa link, means for adjustably carrying the link on the rod, and a fluidtank positioned to receive and support each float on fluid contained inthe tank.

21. An engraving machin including a stylus, an engraving tool and amovement multiplying linkage therebetween, said linkage includingtransverse links hingedly mounted to the frame of the machine, aconnecting link hingedly attached to the transverse links and having ahinge in the center, a movable frame carrying the engraving tool, linksincluded in the linkage pivotally attached to the movable frame, saidlinks being hingedly attached to the transverse links to be movedthereby when the connecting link is moved by the stylus, and meansforming apart of said connecting link for moving the stylus verticallywithoutmoving the hinged connections between the connecting link and thetransverse 1inks,'and means independent of the pantograph linkage tomove the engraving tool vertically.

22. An engraving machine including a stylus, an engraving tool and amovement multiplying linkage therebetween, said linkage includingtransverse links hingedly mounted to the frame of the machine, aconnecting link hingedly attached to the transverse links and having ahinge in the center, a movable frame carrying the engrav'ing tool, linksincluded in the linkage pivotally attached to the movable frame, saidlinks beinghingedly attached tothe transverse links to be moved therebywhen the connecting link is moved by the stylus, and means forming apart of said connecting link for moving the stylus vertically withoutmoving'the hinged connections between the connecting link and thetransverse links, and means independent of the pantograph linkage tocause a relative vertical movement between the engraving tool and thework, said independent means including a control member positioned nearthe stylus to be moved by an operator.

ARTHUR B. SIMMONS.

